Fertile ground

Crop breeding and pesticides are not the only way farmers will be looking to increase agricultural yield to feed a growing population in the future. Globally, fertiliser use is expected to grow exponentially over the coming decades.

But as fertiliser use increases, so do concerns about the environmental effects of the three main nutrients used as synthetic chemical fertilisers – nitrogen, phosphorus and potassium. Nitrogen and phosphorus run-off can damage rivers and lakes. Fertilisers have been used for hundreds of years, but now the environmental concerns are starting to give them a bad reputation with policy makers.

Keith Goulding, head of Sustainable Soils and Grassland Systems at Rothamsted Research in the UK, says fertilisers need to be used more efficiently. “Policymakers that see fertilisers as a bad thing need to know that fertilisers feed half the world,” he says.

“It is incredibly important for sustaining global populations. But there are opportunities for improving on fertiliser manufacture, use and efficiency.”

Fertiliser use is now decreasing in western Europe, following limitations put in place by the EU’s 2003 fertilisers regulation and 1991 nitrates directive.

Goulding says farmers have decreased their use of nitrates as a result, but are getting the same yield by using the fertiliser more efficiently. Prices are also pushing farmers in this direction.

“The current price of nitrogen and phosphorus is as high as it has ever been, so there is a strong incentive for farmers to reduce fertiliser use and increase efficiency,” he says.

“There’s a lot of opportunity through plant breeding to fix nitrogen in the crops, and to recycle manure better.”

While fertiliser use stabilises in western Europe, and farmers there concentrate on using fertilisers more efficiently, in eastern Europe, where much less fertiliser has been used, farmers are now catching up.

The European Environment Agency expects nitrogen mineral fertiliser consumption to increase by about 35% in the new member states between 2007 and 2020. Phosphate and potassium use are expected to increase by 52% and 41% respectively.

A review by the European Commission in 2010 concluded that more fertilisers need to be included in the scope of the legisation and greater environmental protection is needed. However, a Commission spokesperson said it has no plans to revise the fertilisers directive at present.

A green paper is expected in the coming months on improving the efficiency of phosphate use.